Hydrogen and deuterium analysis by heavy ion activation

The use of heavy ion activation as a method for the analysis of hydrogen and deuterium has been evaluated. The irradiations were performed at the 88-inch Texas A and M University variable energy cyclotron. Nominal beam energies were 78 MeV 7Li, 70 MeV 10B, 92 MeV 11B and 129 MeV 19F. Short lived nuclides (e.g. 8Li, T = 850 msec, or 12B, T = 20 msec) were irradiated in air. Longer lived nuclides were produced by irradiating in vacuum. The maximum beam intensities used were 1 μA and irradiations were limited to 1 hour or the half-life of the product nuclide. The beam pulsing system used to limit the irradiation time to the half-lives of 8Li and 12B has been described elsewhere. Thick target yields from reactions of 7Li, 10B, 11B and 19F on 1H and 2H have been determined; activation curves for many of these reactions are presented and interferences are evaluated. Hydrogen has been determined in titanium via 1H(10B,α)7Be at the 100 and 33 ppm levels with relative precisions of 8 to 10%. The highest sensitivity and selectivity are obtained for projectile target combinations resulting in exoergic reactions, where the cross-sections needed for trace detection work can be reached with low velocity beams. The HIAA method studied features high sensitivity for 1H, applicability on thick samples, freedom from interferences and surface contaminants, but lack resolution. (T.G.)